call it a night vs leave off

call it a night

verb
  • To cease what one has been doing for the night. 

  • To go to bed to sleep. 

leave off

verb
  • To desist; to cease. 

  • To omit. 

  • To stop with a view to resuming at a later point. 

How often have the words call it a night and leave off occurred in a corpus of books? (source: Google Ngram Viewer )